A newly designed economizer to improve waste heat recovery: A case study in a pasteurized milk plant

An economizer is normally employed to perform heat recovery from hot exhaust gases to cold fluid. In this work, a newly designed economizer is devised to achieve high heat recovery in a pasteurized milk plant. In the economizer, the hot exhaust gas is divided into two channels flowing up on the left and right sides. After that, it is moving down passing over aligned banks of tubes, which water is flowing inside, in a triple passes fashion. Moreover, three dimensional (3D) models with heat transfer including fluid dynamic have been developed, validated by actual plant data and used to evaluate the performance of the economizer. Simulation results indicate that the newly designed economizer can recover the heat loss of 38% and can achieve the cost saving of 13%.